The present invention relates to systems for shredding materials and, more particularly, to shear shredders in which cutting elements reduce material size.
Shear shredders are well known and are commonly used to reduce material size so that the overall volume of material is reduced for storage or transportation, or so that particle size of the material is reduced to promote burning or combustion of the material in an incinerator or kiln. The most common application for shear shredders is in the field of waste disposal; shear shredders are particularly effective in reducing such items as rubber vehicle tires to chip sizes which promote the burning of the tire material.
A typical shear shredding system is disclosed in U.S. Pat. No. 4,844,363 and includes a support frame which has an open top and bottom and houses a pair of shredder blade assemblies. Each shredder blade assembly includes a central shaft and a plurality of individual, disk-shaped cutter elements. The cutter elements are spaced apart from each other on the shaft so that a pair of cutter assemblies may be positioned so that the cutter elements mesh with each other. The shredder blade assemblies are counter-rotated relative to each other by a single drive motor and gearbox.
Such shredder systems include a feed hopper which is mounted on top of the housing and communicates with the open top of the support frame. The feed hopper includes a feed ram which is protected within the hopper by its own housing and includes a ram face which is reciprocated toward and away from the open top of the support frame and cutting elements by a double-acting cylinder.
It is typical with all such shredder systems that the cutter assemblies are difficult to insert and remove for maintenance, which results in relatively long periods of down time. Such down time subtracts from the productivity of the shear shredder in processing waste material. Another advantage with presently-known shear shredder systems is that the systems must be custom-designed for a particular application. That is, the major components, such as the cutter assemblies, support bearings, drive motors and housing walls cannot be interchanged and reassembled to form shear shredders of different configurations.
Accordingly, there is a need for a shear shredder design in which components, such as the shear cutter assemblies, can be removed and inserted in the field with a minimum of down time. Further, there is a need for a shear shredder having a feed ram which collapses when not in use to provide a maximum opening to the cutter elements. There is also a need for a shear shredder which is of modular construction such that an inventory of components can be maintained to be assembled into a number of different shredder configurations.